As iSCSI SANs become more popular, many organizations have begun favoring an approach to iSCSI storage that draws not only on the familiar Ethernet protocol but on familiar server hardware as well.
"With growing awareness around iSCSI … there is a trend of software-based solutions like those from LeftHand, Open-E, StorMagic and Seanodes [emerging] as alternatives to hardware-centric iSCSI," said Greg Schulz, StorageIO Group founder. "The other piece that helps to fuel this trend is that as more low-end servers are consolidated [with server virtualization], those servers that are made dispensable can be repurposed into storage servers."
While there isn't much hard data available to measure the proportion of server-based to array-based iSCSI SANs being deployed, the trend is reflected in the growing number of startups coming out of stealth with software/server storage packages. Open-E GmbH began North American operations last month after years of selling in Europe, and StorMagic and Seanodes Inc. launched their first products within the last year. Sun Microsystems Inc. also placed a bet on this convergence between iSCSI storage and servers when it melded its server and storage engineering groups last October.
Financial publishing firm Weiss Group Inc., based in Jupiter, Fla., has chosen StorMagic's SM series iSCSI software to add storage capacity. According to Weiss Group systems administrator James Santillo, his company previously had
The company has 65 servers attached to 15 TB of iSCSI SAN storage spread across disk arrays from Network Appliance Inc. and Xiotech Corp. But when Weiss Group went looking for secondary storage, StorMagic's server-based approach and automation features won out.
One of the allures for Santillo was StorMagic's ability to automatically expand volumes and load-balance data on the disks it controls as data grows. "I don't want backup to stop if we run out of storage," he said. "I want [the storage system] to provision on the fly and make sure the backup finishes."
Santillo said that he would use not just for backup, but for primary storage too. "We back up only at night, and we'll use the space left over for file storage," he said. His company is also looking to use StorMagic for remote office storage and disaster recovery. Because of StorMagic's integration with Microsoft's VSS for snapshots, Weiss said that he "can provision any machine on my network to be a recovery server in about a minute." It's also easier, he noted, to create SANs of varying capacities using servers, rather than buying storage in preset array capacities.
That rapid provisioning is a key benefit of the server-based approach, Santillo said. Cost is another. "For 6 TB of storage, StorMagic's price comes out to between $8,000 and $10,000," he said. "We'd be talking about $45,000 for the same amount of storage in an iSCSI array, and for a small business, that would have a big impact on the bottom line."
But the server-based approach also has a disadvantage, Santillo said. StorMagic's product doesn't yet have the redundancy he can get with disk arrays, such as dual controllers and MPIO. "I know they're working on it," he said. "Right now that's the only drawback."
Santillo also hasn't decided to stick with either approach exclusively, because he doesn't want to limit his options as the technology continues to evolve. "The beauty of iSCSI is that it's seamless to bring in something new," he said. "When you go with a Fibre Channel product you might stay with one vendor's technology and not change all that much. In the iSCSI market, there are new products on a daily or weekly basis, and you don't have to stay stuck in one product after a few years when there's something new and better."